The MHD turbulence in the plasma might be another important source of the gravitational wave from FOPT though it is still suffer from large uncertainty [1]}, whose the peak frequency locates at [2]}
\(f_{\rm turb}=2.7 \times 10^{-5}\frac{\beta }{H} \frac{1}{v_b} \frac{T_*}{100}\left({\frac{g_*}{100}}\right)^{\frac{1}{6}} {\rm Hz }\;,\) 
